BIRD Fire Recognition and Comparison with Terra/MODIS

Abstract

Data of the Moderate resolution Imaging Spectro-radiometers (MODIS) on the satellites Terra and Aqua are widely used for global and regional monitoring of active fires. MODIS with their infrared channel resolution of > 1 km do omit small fires, which leads to an underestimation of the total fire radiative power (FRP) release. In order to estimate the significance of this effect, we compared the number and characteristics of fires detected by Terra/MODIS with those detected by the DLR small satellite BIRD dedicated for fire recognition, which provides a resolution of 370 m in its infrared channels and allows the detection of smaller fires than MODIS by a factor of 7. For this purpose, we used data acquired near-simultaneously by Terra/MODIS and BIRD over fires in Siberia, Australia and Portugal. The results show that (1) the FRP of more than a half of the hot clusters, which were detected by BIRD, is below the detection limit of MODIS, (2) MODIS does only slightly underestimate the cumulative FRP in ecosystems where large fires take place and therefore (3) MODIS is hardly suitable for an early fire detection, but it is an adequate instrument for cumulative FRP estimation.